Add VirtRegMap::hasKnownPreference().

Virtual registers with a known preferred register are prioritized by
RAGreedy. This function makes the condition explicit without depending
on getRegAllocPref().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169179 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/VirtRegMap.h b/include/llvm/CodeGen/VirtRegMap.h
index ebf42a3..5fe6297 100644
--- a/include/llvm/CodeGen/VirtRegMap.h
+++ b/include/llvm/CodeGen/VirtRegMap.h
@@ -134,6 +134,11 @@ namespace llvm {
       return getPhys(VirtReg) == getRegAllocPref(VirtReg);
     }
 
+    /// @brief returns true if VirtReg has a known preferred register.
+    /// This returns false if VirtReg has a preference that is a virtual
+    /// register that hasn't been assigned yet.
+    bool hasKnownPreference(unsigned VirtReg);
+
     /// @brief records virtReg is a split live interval from SReg.
     void setIsSplitFromReg(unsigned virtReg, unsigned SReg) {
       Virt2SplitMap[virtReg] = SReg;